https://github.com/llvm/llvm-project/pull/178333 updates the memprof
pass to annotate string literal section prefix.
The StaticDataProfileInfo.cpp provides an analysis pass to reconcile
global variable hotness. It's used by StaticDataAnnotator and AsmPrinter
to look up global variable hotness.
This PR updates the analysis pass to compute the hotness of string
literals.
* When both data access profiles and pgo counters provide a hotness
attribute, use the hotter one.
* Otherwise, use the hotness attribute that's available.
Implementation-wise, the option `AnnotateStringLiteralSectionPrefix` is
moved from MemProf (a transform pass) to StaticDataProfileInfo (an
Analysis pass). Otherwise, there might be errors like caught by CI. Note
https://github.com/llvm/llvm-project/pull/178336#issuecomment-3808537817
is an edited message, and its history shows the intermediate failures
like below. ~My understanding is~ Preliminary LLM study (:)) shows that
the error manifests in PowerPC but not X86 due to cmake variable
differences.
```
FAILED: unittests/Target/PowerPC/PowerPCTests
...
>>> referenced by CommandLine.h:1437 (/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/Support/CommandLine.h:1437)
>>> StaticDataProfileInfo.cpp.o:(llvm::StaticDataProfileInfo::getConstantSectionPrefix(llvm::Constant const*, llvm::ProfileSummaryInfo const*) const) in archive lib/libLLVMAnalysis.a
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
```
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